如何在新位图上绘制已知大小的矩形？

Question

我有这个代码：

Bitmap newbmp = new Bitmap(512, 512);

foreach (Point s in CommonList)
{
    w.WriteLine("The following points are the same" + s);
    newbmp.SetPixel(s.X, s.Y, Color.Red);
}

w.Close();
newbmp.Save(@"c:\newbmp\newbmp.bmp", ImageFormat.Bmp);
newbmp.Dispose();

代码不在绘制事件中。

然后我有一个 pictureBox1 的绘画事件：

private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
    if (cloudPoints != null)
    {
        if (DrawIt)
        {
            e.Graphics.DrawRectangle(pen, rect);
            pointsAffected = cloudPoints.Where(pt => rect.Contains(pt));

            CloudEnteringAlert.pointtocolorinrectangle = pointsAffected.ToList();
            Bitmap bmp = new Bitmap(pictureBox1.Width, pictureBox1.Height, PixelFormat.Format32bppArgb);
            CloudEnteringAlert.Paint(e.Graphics, 1, 200, bmp);
        }
    }   
}

在绘画事件中，我正在绘制一个矩形。变量 rect.

我想在newbmp 上绘制矩形rect。保存newbmp后在他身上画这个rect

如何在 newbmp 上绘制矩形？

Answer 1

您应该从位图创建一个Graphics对象以在上工作：

.. Bitmap newbmp = new Bitmap(512, 512); foreach (Point s in CommonList) { Console.WriteLine("The following points are the same" + s); newbmp.SetPixel(s.X, s.Y, Color.Red); } using (Graphics G = Graphics.FromImage(newbmp)) { G.DrawRectangle(Pens.Red, yourRectangle); .. } newbmp.Save(@"c:\newbmp\newbmp.bmp", ImageFormat.Bmp); newbmp.Dispose();

对于其他 Pen 属性，例如 Width 或 LineJoin，请使用此格式：

using (Graphics G = Graphics.FromImage(newbmp)) using (Pen pen = new Pen(Color.Red, 8f) ) { // rounded corners please! pen.LineJoin = System.Drawing.Drawing2D.LineJoin.Round; G.DrawRectangle(pen, yourRectangle); //.. }

如何在新位图上绘制已知大小的矩形？

How can I draw a known rectangle size on a new bitmap?

.net

c#

winforms